Fluorescent agents are used for various uses, among which the following are typical. In photosensitive resin-related fields, additives used as constituent materials include penetrant additives for the purpose of increasing visibility in nondestructive inspection methods such as their representative penetrant flaw inspection methods, and additives for optical inspection (AOI) in photoresist-related fields that have increasingly become automated with higher speeds in recent years. They are also used as photosensitizers for dry films used for patterning of circuit boards. Other uses include as additives for ultraviolet absorption films that cut harmful ultraviolet rays from sunlight and ultraviolet rays generated from illumination devices such as fluorescent lamps that attract flying insects, and as additives for ultraviolet absorption films that cut ultraviolet rays from sunlight and fluorescent lamps to prevent discoloration of photographs and liquid crystal displays.
On the other hand, compounds with certain types of coumarin backbones are known as fluorescent agents with ethynyl groups in the molecule. Specifically, substituted and unsubstituted 3-phenylethynylcoumarins are disclosed as organic coloring agents in Patent document 1. Although their purposes of use differ, Patent document 2 mentions that aromatic compounds containing acetylene groups (ethynyl groups) can be used for vapor deposition polymerization. Vapor deposition polymerized monomers are used as vapor deposition polymerization thin-films in electronic light emitting elements. The aromatic ring backbones may be compounds with various and diverse backbones, and coumarin is disclosed as one of them.    [Patent document 1] WO01/68635A2    [Patent document 2] Japanese Unexamined Patent Application Publication No. 2002-69013